The engine may develop a stalling and/or no start condition due to a failed crankshaft position sensor.Google+
Car Problem Reports
Mercedes-Benz SL55 AMG Engine Performance Problems Due to Crankshaft Position Sensor Failure
Mercedes-Benz SL55 AMG Problem
Average Mileage: 45,334 mi (30,002 mi - 56,000 mi)
This low mileage car will often not respond to the remote key opening command. Once in, starter will not respond to either the card/button start nor to the key in ignition start.
I have had the position sensor replaced at the cost of $1,400, but the problem is even now worse.
I have had the left door locking assembly replaced as well and have dumped about $2500 in repairing this problem. Still no success.
Driving to california from las vegas the engine sudenly stops in the middle of the desert 165 miles from vegas.car had to be flatbeded 200 miles,for repair....bad crank position sensor,never had this type of diaster with other cars,
Visitor, 2004 Mercedes-Benz SL55 AMG, 50,000 mi
Limped to dealer (after multiple stalls and restarts - replaced sensor and now fine.